Combinatorial testing has been shown to be a very effective testing strategy. Most work on combinatorial testing focuses on t-way test data generation, where each test is an unordered set of parameter values. In this paper, we study the problem of t-way test sequence generation, where each test is an ordered sequence of events. Using a general labeled transition system as the system model, we formally define the notion of t-way sequence coverage, and introduce an efficient algorithm to compute all valid t-way target sequences, i.e., sequences of t events that must be covered by at least one test sequence. We then report several algorithms to generate a set of test sequences that achieves the proposed t-way sequence coverage. These algorithms are developed as the result of a systematic exploration of the possible approaches to t-way test sequence generation, and are compared both analytically and experimentally. The results show that while these algorithms have their own advantages and disadvantages, one of them is more scalable than others while exhibiting very good performance.